Age-resister



5 Considerable difiiculty has been axperienced in available'hence is'pre'ierred touse the preferred 6'0 i goods: in addition tot-he natural deter ioration propoxy diphenylamineieither normal propyl or '65 115 It has now been found that a class of substances amine and isopentoxy diphenylamine give com- 70 520, tion of the transverse fissures or so-called flexing amine) the results are distinctly inferior even to 3m biphenyl, or even naphthalene may be used in 1. The method which comprises treating rub- 85 alkoxy up is preferably located in the p primary or secondary alkyl group containing 90 All The rubber may also be treated therewith in other 9 e5; weight of rubber, 50 parts of gas black, 5 parts of one carbons. m0

501 vulcanized under pressure in a heated mold for sit Patented Jul 10, 1934 1,965,948

non-.misrsrnn L.,Semon, Silver Lake Village, Ohio, as- 'srgnorto'l'he Goodrich Company, New 1 York; N? Y., a corporation of New York No Drawing. Applioationnugust 3,1933, a a 1 3, Serial No. $83,417?

"is Claims. (01. 1s 5o) invention relates-to preservation of ing from 3 to 4 times as long as the sameccniposh rubber, and particularly; lite-therpresermtion "of tion without these substances. However, this rerubber compositionswhichare siibjected torapid suit is not appreciably better than can be atiyrrepeatedi strains. i Y tained by certain commercial anti-oxidants now the past in controll-ingthe deterioration of rubber, substances referredto above, which the alkyl and particuiarlyv of vulcanized rubber goods which group is either primary or secondary and contains are subjected to rapidly repeatedstrains, such as more two carbon atoms, but not more than pneumatic tires, belts andthe like: Such rubber two methylene "carbons. For instance, if pwhich rubber undergoeswh'enexposedsto thezair, iso-propyl) is used in the proportions set forth tendto develop fissures in a direction transverse above, the, rubber resist flexing from 8 to 10 to-the' strains, whichfissures may lead to a pretimes as long as the untreated rubber. Secondmature failure of the goods. ary butoxy diphenylamine, isobutoxy diphenylwhich may be designated as alkoxy diarylamines parable results. On the other hand, if tertiary possess the property not only of greatly retardalkyl groups are used (tertiary butoxy diphenyling the ordinary deterioration or rubber, but of amine), or if the alkyl group contains too many greatly increasing its resistance to the formamethylene carbons (normal butoxy diphenylcracks referred to above. those attained by the use of the methoxy and The substances which fall within the class ethoxy compounds first mentioned. which forms the subject-matter of this invention It is to be understood that the invention is not have the general structural formula limited to the specific embodiments set forth above for illustrative purposes, but that, on the R'NHR-O A contrary, it is not intended to limit it except as where R represents an aromatic nucleus, prefermay be required by the prior art and as set forth ably a simple benzene nucleus, although other in the appended claims.

nuclei such as those of toluene, xylene, cumene, I claim:

s m s s, d A represents an alkyl up, p f her with a substance having the formula erably a primary or secondary alkyl group containing more than two carbon atoms, but not H NHR OA more than two simple methylene carbons. The h i R i n aromatic nucleus and A is a position relative o t a o t o ese more than two carbon atoms but not more than substances are preferably added to the rubber t methylene carbons, before vulcanization in small proportions, usually 2. The method which comprises treating rubbetween 0.1 and 5% of the weight of rubber used. her with a substance having the formula ways, such as by applying the substances to the V surface of the rubber. wherein R is a benzene nucleus and A is a primary For example, a pneumatic tire tread composior secondary alkyl group containing more than tion may be prepared by mixing 100 parts by two carbon atoms but not more than two methylzinc oxide, 3 parts of pine tar, 3.5 parts of stearic 3. The method which comprises treating rubacid, 3 parts of sulphur, 1.25 parts ofmercaptoher with a substance having the formula benzothiazole and 1 part of one of the substances referred to above. This rubber composition is minutes at 280 F. When the substance added wherein A is a primary or secondary alkyl group to the rubber composition is such an alkoxy dicontaining more than two carbon atoms but not arylamine as p-methoxy diphenylamine, or pmore than two methylene carbons.

ethoxy diphenylamine it is found that the rubber 4. The method which comprises treating rubis capable of withstanding rapidly repeated fiexher with p-normal propoxy diphenylamine. g g

5. The method which comprises treating rubber with a substance having the formula wherein A is a branched chain alkyl group.

6. The method which comprises treating rubber with p-isopropoXy diphenylamine.

7. The method which comprises treating rubber with p-isobutoxy diphenylamine.

8. The method which comprises vulcanizing rubber in the presence of a substance having the formula aga."

wherein A is a primary or secondaryalkyl group containing more than two carbon atomsbut not more than two methylene carbons.

9. A rubber composition comprising rubber an a substance having the formula wherein R is an aromatic nucleus and A is a primary or secondary alkyl group containing more than two carbon atoms but not more than two methylene carbons. r

10. A rubber composition comprising rubber and a substance having the formula wherein R is a benzene nucleus and A is a primary or secondary alkyl group containing more than two carbon atoms but not more than two methylene carbons.

11. A rubber composition comprising rubber and a substance having the formula ONE-Ga wherein A is a primary or secondary alkyl group containing more than two carbon atoms but not more than two methylene carbons.

12. A rubber composition comprising rubber and p-normal propoxy diphenylamine.

13. A rubber composition comprising rubber and a substance having the formula wherein A is a branched chain alkyl group.

14. A rubber composition comprising rubber and p-isopropoxy diphenylamine.

15. A rubber composition comprising rubber and p-isobutoxy diphenylamine.

16. A vulcanized rubber composition which has been vulcanized in the presence of a substance havingthe formula wherein A is a primary or secondary alkyl group containing more than two carbon atoms but not more than two methylene carbons.

WALDO L. SEMON. 

